Hello, all. I'm taking the plunge with the Mystery Amp! I've read through this entire thread. I tip my hat to those brave souls who jumped in the water before me!

Over the years I've upgraded my speakers, digital front end, and, last year, turntable/phono preamp... and all of it has been amplified by a heavily modified Dynaco ST-70. By "heavily modified" I mean all that is original is the chassis and transformers! It's been a fun DIY project and it still performs surprisingly well, with lots of magic. But.... it's probably the weak link. Even though I have done the power supply upgrade, and a decent driver board upgrade (Triode Electronics) I just itch for something a little more... pure, with a bit more clean power.

I've been drooling over Decware amps (and others) for a while now. But, I wanted more power than the Torii and the dual monos are just too far outside of my budget. So when I recently discovered this new amp it just hit all the right buttons. Hoping it's the last one I ever buy! What specifically drew me to this amp: (1) Dual mono design. Just makes good sense (2) Being able to use a variety of power tubes... I have lots of 6CA7/KT77/EL34 types lying around. I've never heard 6L6 type tubes in operation, so this will be fun (3) An intelligent biasing system. This is something I've always wanted. And those analog meters... drool (I'm also a ham radio nerd and have done radio/audio stuff so meters make me happy). (4) I am intrigued by the lack of global negative feedback. I don't see the existence or lack of global negative feedback to be a black and white issue, but I have a sneaky suspicion that a lot of the good things people are hearing with this amp has to do with a type of sonic purity in the signal path that may reflect a lack of global negative feedback. So cool beans. (5) Made in the US. This is not a slam on other countries or a jingoistic rah rah thing, it's just that so little stuff is made here and I like to support local(ish) businesses when I can. Oh, (6) It looks fan-f***ing-tastic. I'm going with the maple frame - a brighter happier look . The only other upgrade I chose was the stepped attenuator - I just will feel more at ease with that.

So now that I'm officially on the build waiting list I thought I'd chime in and say hi. I'll be sure to share my impressions when that lovely heavy package makes its way to my doorstep in a couple months.

I've played with a few Dynaco amps over the years, and was tempted to build one from scratch using the Triode parts (they are Chicago based). The ZMA is for sure in a different league than the Dynaco stuff. Your ST-70 will be quickly relegated to your "second system" LOL

I look forward to hearing what you think of the Mystery Amp when it arrives. I swear every 100 hours the amp bumps up a notch - so you'll have a lot to look forward to.

I did a little searching on negative feedback a couple weeks ago after a listening session and below is some information I found. NOTE: I pulled these references from the internet so they must be fact.

Excerpts from an interview with Charlie Hansen from Ayre (Ayre Audio only produces solid state amplifiers, so this isn't specific to tubes)

Feedback also happens to improve the measurable characteristics of amplifier circuits by increasing the bandwidth, reducing the distortion (at least for steady-state signals), and lowering the output impedance. And this is why its use became so universal in audio circuits. For decades, it was assumed that there was a direct correlation between measurements and sound quality. But there is something about feedback that we can't really measure that seems to have a detrimental effect on the sound quality of real musical instruments. It seems to be related to time domain performance.

Time domain performance? Can you elaborate? Well, the simplest way to think about this is that feedback cannot respond to an error until after the error has occurred. And this correlates pretty well with what we hear. Compared to a zero-feedback design, adding feedback seems to overemphasize the leading edge of transients. This can give a more "spectacular" sound in the hi-fi sense, but it is less musically natural than a zero-feedback design. And this sonic "thumbprint" seems to exist under a wide variety of conditions. On the other hand, a zero-feedback design becomes very chameleon-like from a sonic standpoint. In my experience, the zero-feedback designs will "get out of the way" of the music with a wide variety of source material. And with our designs there isn't any reason to use feedback.

The below reference is from an article comparing SS vs. Tube, but there was some discussion on feedback:

In Atwood's opinion, "Some of the differences in the audio qualities between tubes and transistors have to do with the inherent physical properties of the devices and with the circuit topologies and components used with each type of device. There is no way around it: linear [triode] vacuum tubes have lower overall distortion than bipolar transistors or FETs, and the distortion products are primarily lower-order...the clipping characteristic of tubes is actually not much softer than transistors, but feedback tends to 'square-up' the clipping. Thus, the heavy feedback in most solid-state designs gives them worse overload performance.

"A low- or no-feedback design can be driven harder without audible distortion," Atwood continued. "High feedback also can lead to transient intermodulation distortion (TIM), caused by clipping or slew-rate limiting within the feedback loop." See following table for a comparison of the attributes of tubes and transistors in audio applications."

Speaking about solid-state designs, Whitlock asserted that they † †"...depend on huge amounts of negative feedback to 'fix everything', including crossover distortion. Op amps commonly have open-loop THD in the 20 percent to 70 percent range. Stabilization generally requires open-loop gain to fall at 6 dB per octave. This means that, for ultrasonic input signals, the op amp has little gain margin to fix its own distortion. The ultrasonic signals, along with distortion products, are fed to the next stage for further distortion and intermodulation. This intermodulation creates audible, but non-harmonically related, artifacts which contaminate the noise floor and mask many subtle features of the music."

Negative feedback can reduce the total quantity of distortion, but it adds new components on its own, and tempts the designer to use more cascaded gain stages in search of better numbers, accompanied by greater feedback frequency stability issues. The resulting complexity creates distortion which is unlike the simple harmonics associated with musical instruments, and we see that these complex waves can gather to create the occasional tsunami of distortion, peaking at values far above those imagined by the distortion specifications.

In the very early pre Decware days during the 17 years between my first wife and my second wife, I did my serious listening every night from 10:45 P.M. to 2:45 A.M. †During this time, my corner horns were my primary reference speaker and were on either side of a 6 foot opening into another room of equal size which opened up to a third room of equal size. The speakers were a mere 13 feet apart putting me at 6 feet back due to the 45 degree toe in. Of course with an opening in front of me with some 30 feet of optical depth I certainly didn't feel like I was sitting that close.

Just to mess with my brain, I put a baby grand piano in the second room behind the speakers... that was fun. It was especially fun when listening to piano music. The typical recording put the piano right where it actually sat. Good stuff

I learned about negative feedback in this place.

The first time I lifted the feedback on a tube amp in this room I almost pissed my pants. You see the stereotypical soundstage I was used to went 6 feet behind the speakers (on a good night). With the feedback removed the sound stage suddenly exploded back into the back wall of the third room. That was 30 some physical feet but it sounded like 90. †

This illusion became an obsession of mine that lasted for several years where the depth of the sound stage became the ruler by which one amplifier's stripes were measured against another. I can remember many times when two amplifiers were tried and... same frequency balance, same bass, same dynamics, same sound but one went back to the third room and one didn't. †Winner!

It doesn't really take a lot of math to understand that it takes a finite amount of time for the signal to pass through an amplifier and during that process it gets delayed more at some frequencies than others aka phase shift. †

So if you take a signal from the output of the amplifier that is delayed and no longer in-phase relative to the input at most of it's frequencies and feed it back into the input... the end result is smeared time and smeared phase. It's so smeared in fact that the low level ambient information that contains the sound stage depth cues is completely destroyed. Add to the casualty list: transparency, openness, presence and micro detail and of course ambience. †

Taking the momentum of this thought a bit further, imagine taking the tube circuit poisoned with negative feedback and exchange it for solid state with 10 times as many parts and 4 to 10 times MORE feedback. hmmm yummy. Then invent CD's. Take away the last hope and make us listen to our miserable crap on an equally miserable format. After all, since CD is missing some 40 percent of the music, and solid state amplifiers gross amounts of negative feedback kill about that same amount, no one will even notice.

Frankly I was mortified. †Decware was born from that disgust.

On a happier note, despite the corner horns having perhaps the best bass ever... and extension to the mid 20's... †Imagine the following: †The house was over 150 years old. There was a basement. I build a concrete horn in the basement that wrapped around the furnace. †It has a throat that was 3 inches x 48 inches and a mouth that was 10 feet by 48 inches with a total length of 18 feet. The wall thickness of the horn was 4 inches on one side and infinity on the other being underground. I estimate it weighed over 3000 lbs for just one side wall of the horn. †(grin)

With a single 12 inch woofer I cracked my basement in 72 places in on the very first test. The bass from this sub when you were upstairs in the listening chair was so fast you perceived the kick drum coming out of your chest.... agh the good old days... †when i was still crazy.

I remember that sub-woofer you build out of the curvature of your basement. It was practically a bucket list item for me to sit inside it when I first went to visit you at the old place. I never did get to hear it though.

That's great info on the negative feedback. The reasoning behind it makes sense, but I've heard time and time again how if the electricity is moving almost at the speed of light, it would be impossible for us to perceive the difference of time in the negative feedback. But then time and time again, I find amps that don't smear the micro-detail and timing (and digital with the least jitter) always seems more life like and those ambiance cues pop out.

I think there is still a lot about sound and how the brain processes it that we don't know, or that scientists may know, but haven't explored because they really don't see a reason too. (or how to make money off of the research)

....nope....the CSP3 & ZMA win... . ...not about the money either...if the AR stuff was better (either one)...I would have bought it. Being able to also dial in the Voltage output to my ZMA for my Anthony Gallo Reference 3.1's...is a shat your pants factor too.

Hello, Folks. Iím new to Decware, and to this forum. Since my Mystery Amplifier shipped today, Iím thinking itís a good time to introduce myself. My handle is Alaska Dave, out of Juneau, Alaska.

Iíve been in the audio game seriously something over 20 years. Like many of you, Iím dedicated to the purest, most natural and present sound I can get. I like to do a major upgrade to my system about once per year. Since 2000, Iíve been using an Art Audio Diavolo amplifier (13 watts, SET, Class A, no negative feedback, KR 842 VHD output tubes). This is a superb single-ended amplifier, but is showing its age, so Iíve been looking toward a new amp for quite a while. End of last year I was trying to narrow the field, and the Mystery amp came up on the radar. Itís apparent potential and promise intrigued me, and after a couple of conversations with Steve Deckert, I placed the order in January. Frankly, the review of the Torii Mk III in Tone Audio gave me confidence, too. So the waiting game is almost over.

My speakers are Marten Miles 5s, Accuton drivers, 90 dB, new last spring. I had the Miles 3s for seven years prior, and the 13-watt Diavolo drove them easily (substantial power supply there, too). The speakers are highly resolving, accurate, and musical, which is why I upgraded to the new model. My source is an EAR Acute 3 DAC/CD player with tube output stage, with hi-res music files pending, soon as I figure that out. Audience aR6-TSS power conditioner and Acoustic System Liveline cables.

Actually, besides being a dedicated audio nut, Iím a very small, out-of-home, two-channel, audio dealer in Juneau. I keep up with the market very closely; Iíve attended all but one of the 10 RMAF shows and several CES and other shows. And Iím retired, which is a wonderful thing!

This Forum has been impressive as to the breadth and depth of knowledge, and for its dedication to the art. I look forward to beginning the Mystery amp experience, and to sharing it with all of you. And let me know if youíre ever in the neighborhood! Good listening!

With the experience you have in two channel audio, I really look forward to your reports on the Zen Mystery Amp. While I think I have a decent ear for listening, I don't have the experience many of you have to (physically or mentally) compare the ZMA to other modern amps.

Congrats on the imminent arrival of your new amp!

Just give it about 100 hours before you really give it a listen. I swear it seems to step up a notch about every 100, and that first step for me was about 125 hours.

I am glad to read you have great Speakers & Cables! You will get to hear what the ZMA can really do...(like me). I use a pair of Gallo Acoustic Reference 3.1's currently an Kimber Select 1030 IC an Select 3035 Speaker Cables.

I remember a gentlemen at the 2005 DecFest that was a Dealer for Art Audio...and he was there to hear if Decware was hype. He left knowing these Amps can compete with Art Audio.

I am very pleased with my ZMA & CSP3 combo! †I am now looking at your choice in Speakers! I am always out for improvement... .

Has anyone here done any tube rolling? I just tried some cryoed KT88 Gold Lion tubes. I liked the sound but didn't continue because I could not adjust the bias to the 50 mark. It seems I'm bottomed out on my adjustment at almost 70 on gauges. Thought I would check with you guys while I'm waiting for a reply from Steve.

Steve has a specific bias window set for safety reasons. If you've got the bias knobs cranked full right (which makes the needle go left) and you aren't anywhere in range, then it's good you pulled the plug on that. I believe Steve said you could pretty much use any of the common output tubes you wanted, as long as you're able to bias it at 60ma or less. Any more than that would strain the power transformers and run them to an early demise.

tube rolling for ZMA. Yes, I have done with Siemens E88CC ($370 for quad), RCA 6L6GC ($380 for quad) and RCA JAN OA3 ($18 for pair).

The sound quality of ZMA with stock tubes is unquestionably superb . But I need more in lush midrange female vocal, sparkle treble and powerful bass or bass slam.

My first plan is to burn in ZMA with stock tubes for >300 hrs first to know the sound. Then do tube rolling step by step to observe sound quality changing. But ZMA with stock tube's sound is so good that I imagine what if I put Siemens E88CC tubes in, how much is the sound improvement? I cannot wait, I change plan to put in Siemens E88CC tubes first 3 days ago. Midrange sound is more lush, both high end and low end extend more, more holograph sound stage. But speed is slower than stock tube. The fun or PRAT is reduce a little. But overall sound improvement is very satisfy. I replace KT66 with RCA 6L6GC next day. There is more dense sound and more bass. Now speed come back, PRAT is same as stock tube now. But bass is little boated, not well control. Then I put in RCA JAN OA3. OMG, it is the last jigsaw. RCA JAN OA3 make over all sound dense, coherent and PUNCH SLAM bass! Boated bass disappear and very well control now.

Now I get all, lush midrange female vocal sound to die for of tube amp reputation, sparkle high and PUNCH SLAM bass! Playing with heavy rock music, you can feel wavy air movement of bass. It is very very scare realism! If you run at 56 ma, it likes discotheque. If you run at 52 ma, it likes stadium rock live concert. The strange is that you just listen at normal SPL 80-93. It is scale down at any SPL, no need to get loud of 100 SPL to get rock live concert feel.

Is it worth to change tubes as above? In my system, the answer is absolute yes! I will report more when have more hours on these tubes. It is improving.

I too have run out of bias adjustment trying to achieve the desired 50mA. This is with the standard tubes. I can just about get 50mA and I do achieve it on one channel. In my case I know part of the problem is down to my mains voltage of 250v instead of 230v-240v.Adding a 500W mains re-generator I was using in another system allowed me to drop the voltage down to 230v. This allows for a bit more level adjustment but it's still close to the maximum. I've emailed Steve about this but had no reply.

I've had my ZMA for about 5 week and apart from this one minor issue I'm finding it to be a superb amp. Before the arrival of the ERR's a week ago I was wondering what the ERR's could possibly add. Well, the new ERR's take the system to a whole new level. The openness of the sound I immediately noticed. But for me what makes the ERR's very special is what they do for the bass response in my small room. Nothing else I've tried has come close to giving me the sort of response I get at my listening position with the ERR's. The ZMA in combination with the ERR's totally transforms much of my music.

LR, #1062, ....I don't know if the ZMA has plateaued? I have the CSP3, now in its 46th hour....and the involving music with this Pre, I am getting-does keep getting better. No hyperbole...I was not a fan of the Torii III...so I sold it. .......the CSP3 & ZMA combo is truly a musical journey every time I turn them on.

LR & Palomino, have fun at Axpona! I would have been there to meet you guys... . I will be partying in Northern Cal gentlemen, being a Stanford dad!

Will do Stone. Let us know if there are any other products we should check out.

I more or less wander around, visit a few rooms where I know the products and go to some of the completely over-the-top rooms for fun. The Direct Stream is on our list. I also am a sucker for any rooms with horns, single driver setups and triode amps. Given the discussion here, I may have to add reel to reel rooms as well.

I bring my Shazam equipped phone and get as many music ideas as I can. There are a lot of audio show clichťs played, but last year I picked up some good new artists.

I will be listening to see if there are any ZMA toppers and if so, what price point they sell at.

I wonder that Otari MX5050 sounds compared to the master tape console.

That's a good question. I've been doing a lot of research to get up to speed on R2R, and from what I've read, the heads on the pro studio decks are supposed to have higher top end extension. The MX-5050 was designed as a pro-sumer/broadcast deck. In fact, mine came out of a radio station and has a set of two track heads (aka half-track) and a big mono "full track" head which is kinda useless to me. The MX-5050 is fine for our purposes - playback, but there is a shop that makes a studio grade (upgrade) head for this deck that brings it more in line with the studio decks like Steve has; I believe they said the new heads extend to 30khz.

That said, Steve said that I had uncovered the *best* $400 source he'd ever heard, and was tempted to try and trade me one of his big studio decks for it as the 5050 seemed to record just as well as his second deck.

Steve tried to prove this to me by playing a recording of one of his two track radio station tapes he made for me...but it honestly sounded kinda rough. Long story short, everything we did that night sounded bad, even going back to his big Otari MTR-10, radio master tape, and two different Mystery Amps (mine, and someone's brand new one that got shipped out that night). *Nothing* we did sounded good and nothing Steve, Dave or I could think of was resolving this issue. We all shrugged and said

I've since taken the deck and my ZMA (now with balanced inputs) home, and even the crappiest tape I got off craigs list sounds better than what we heard that night. So I still have no idea what it was, but everything's OK now.

I'm confident the MX-5050 is a great source; one just needs to find one with good heads (the correct ones! LOL), and learn how to clean and maintain, and find good media for it. In the Decware Tapefest thread I've started a listing of shops that sell "studio masters" or just one generation off the masters. More on all this in that thread, or if Steve puts together a Tape sub-forum.

So I've had my first real listening session since getting the XLR inputs on the ZMA, and I had some friends over for a listen. One friend I've been on this listening journey with since I bought my first amp from Steve back in 1998. The other friend was curious what this audiophile thing was, and is a pretty smart dude (in general) who loves music, so I invited him to join us tonight.

Long story short, I played some of my favorite audiophile tracks, plus some classic stuff like Pink Floyd and Crosby, Stills, and Nash just to prove my setup does more than female voices and jazz (which it seems to be what 98% audiophile tracks seem to be), then took a couple requests, and finished up the night by playing some of the Twins Soundtrack (a copy of Steve's Master), and...get this, Allied Electronics commercials from April 1959 that came in a box of tapes I picked up off Craigs List.

I have to say, this was the *best* the ZMA has *ever* sounded! I thought I was done with the "wow, I've never heard *that* before" thing when playing old favorites, but there is was again! Another level of detail and depth and soundstage that I didn't have before. My friend Jason was just like, Wow, that's the best I've ever heard Pink Floyd's The Wall - and I pointed out it was the MFSL 24k CD (FLAC) that he never liked compared to his standard copy. We both heard details we'd never heard before. And my friend Nate who'd never experienced anything like this before...well, I think the ZMA was too much for him...he was stumbling over his worlds just trying to say WOW. He was pretty flabbergasted.

Now, my friend Jason who's been listening with me for 15 years, he heard the ZMA when it was still pretty new...not quite 100 hours I think, and we both thought the high end was a bit edgy and dry, and I caught him looking at me like "you spend how much on this..." Now that the got 400+ hours (and XLR inputs) he was floored - he said he couldn't understand how I heard this potential in an amp that sounded that rough when it was new. He said everything I described to him 3 months ago was there now; the detail, the rich harmonics that bring voices and instruments alive, and the dynamics that just make everything pop.

And the new guy was like...wait, there's only two speakers playing here? No center channel, or surrounds? He'd heard of soundstage before, but this was the first time experiencing it.

So after such an amazing digital show (all from the Oppo via XLR, controlled by my cell phone), the tape only floored them all over again. The Twins soundtrack was so dynamic and live. Neither one of them could put their finger on how or why the tape sounded so much "better" than the digital tracks "it just did". I still have a lot to learn about tape, and Steve's copy isn't 100% right IMHO, but it was a good showing. With some tweaking on my part, and a slightly better recording, this could be a whole lot better. And my friend Jason who's a very science geek said that he was very skeptical of tape, that he really believed that CD was already to the limits of what we could hear, but that special something that comes from Analog really changed his mind.

And to finish up the night, we all got a great laugh out of these 55 year old commercials for Allied Electronics. It was just some typical late '50s jingles and an announcer with a great voice, but it sounded so live and present, like he was here in the room with us trying to sell us a stereo (only 149.50 and only $5 down!). That was certainly a great way to end the night, and just blew our minds how a 55 year old tape could be so fresh and present.

Sorry to ramble and gush so much. It's just that I thought this amp was done, it's at its final plateau and will sound this good forever. I really believe these XLR with my Oppo took it up another notch.

We had friends over a couple weeks ago and my friendís boyfriend was showing some interest in the stereo equipment. I think it was the blue lights/screens on the PSA gear that initially caught his attention. He then started looking around and asking questions (why are the speakers so far into the room?, etc). He isnít into audio and had never seen a tube amplifier which further intrigued him. I asked him if he wanted to listen. He said sure and I sat him down in the sweet spot. His reaction was very similar to what was described below:

And the new guy was like...wait, there's only two speakers playing here? No center channel, or surrounds? He'd heard of soundstage before, but this was the first time experiencing it.

He initially said, wow, this would be great for movies because he thought I had a multi-channel setup going. When I told him that all of the sound was coming from the two speakers, he couldnít believe it. He pointed at my diffusion panels and said ďthose arenít speakersĒ? I think it really blew his mind. He couldnít stop talking about it for the rest of the night. It was pretty entertaining.

† † † I basically had the same experience as you had, except the only thing in my system that changed was the †little magic box Steve made for my tape machine to use XLR's.

In this case, I thought my PS audio DAC also has XLR outs, why not give it a try. It was uncanny good. Everything you said changed in your system, I concur with. So go back and try using the RCA's again and let us know if it has as much to do with the Steve's version of an XLR converter or was it really another stage in your Mystery amps break in?

I know Steve bought the little XLR to RCA stand alone box, which he thought sucked (you may have been there to hear it) so he then built one in a Zbox case with volume controls and it is awesome.

Dave, Sounds like you have a good setup for that. My imaging and soundstage are the weak points because of my L-shaped room and the fact that I've not finished building my diffusers. I think I'll be at that happy point that Lon is †at once I get my room better dealt with. I just need to redesign (make more simple) my diffusers, or come up with a better way to mass produce them error free.

Zygi, I saw a box like that when I visited Steve, but I wasn't really paying attention to it. I was more focused on Tape Stuff than the XLR ports, but now I'm seriously looking at the XLRs, as it's the only explanation as to why the ZMA has really taken a step up. Honestly, I thought I was done with the "I've never heard that before!" thing. I'm giddy all over again, like I got a new amp. :)

I don't know the original disc. I got it off of The Real Deal, Greatest Hits vol 1. I think its the best produced track on that disc despite being a live recording. I also use Riviera Paradise as a test track.

In this case, I thought my PS audio DAC also has XLR outs, why not give it a try. It was uncanny good. Everything you said changed in your system, I concur with. So go back and try using the RCA's again and let us know if it has as much to do with the Steve's version of an XLR converter or was it really another stage in your Mystery amps break in?

My ZMA has the XLR inputs and I still haven't tried them. Been dragging my feet on XLR cables for weeks. This really is the motivation I needed. I hope they sound as good as the little black box with my PSA DAC :)

MG-944 on spikes

Do these make an improvement? My 944's are sitting on carpet at the moment.

Dave1210, my biggest improvement recently was to get my speakers off of the carpet. I recently acquired a pair of JanZen zA2.1's and they didn't come with carpet spikes. I finally got around to ordering Mapleshade speakers platforms with brass spikes and now those speakers sound incredible with the ZMA. It was a huge difference. I do have the dreaded L shaped room so nothing's perfect.

Do these make an improvement? My 944's are sitting on carpet at the moment.

Yeah, for sure; the resonation of the floor will damage the sound coming out the speaker - the frequency depending on the shape/size/wobble of your floor. Isolate the speakers and let them speak!

Quote:

Apparently, the designer suggests that a specially constructed cable with XLR's on one end and RCA's on the other is a superior way of doing things.

This is counter intuitive - but I'd like to know more. I'm still trying to figure out why the ZMA sounds better with the XLR - I know it has more voltage, then there is the Jensen transformers, and Steve said something about how a good XLR setup can improve the sound like a preamp. He did say I might be surprised by how the Oppo sounds using XLR, but I didn't fully understand why.

in regard to xlr connections. i had a wonderful cary 120S big tube amp for a good while. when i changed from single ended to balanced, the sound was so much better that i never considered going back. on that amp, the balanced impedence was different and i think it just worked better with the preamp and speakers which accounted for the change. must have allowed them to work in more comfortable ranges.

I have been a long time lurker curious about picking up a ZMA when funds permit.

It is interesting to hear of LR's improvement after adding XLR's. †I remember reading about the DIY nCore amps that come standard with XLR inputs. †

Apparently, the designer suggests that a specially constructed cable with XLR's on one end and RCA's on the other is a superior way of doing things.

With this option for the ZMA, is this a better sound quality option?

PS. †Thank you all for sharing all of your interesting experiences.

tes

With a fully differential balanced source, like my tape machines and DAC, I find that using an XLR to RCA cable completely sucks by comparison to using the transformer. † The change you hear isn't the amplifier, it's what happens to the source. †Granted, no two sources are alike and some might sound fine with one side of the balanced output shorted to ground (what happens when the XLR to RCA cable is used) but my guess is most won't.

Also understand before going gaga over balanced outputs on various components make sure you know how it was balanced. †A) Differential Circuit †B) Single Ended Circuit with Transformer Balanced Outputs †C) Single Ended Circuit with OpAmp driven differential circuit or D) Placebo XLR jack that's not actually balanced at all. †

Do these make an improvement? † My 944's are sitting on carpet at the moment.

Dave,

I have brick floors so quite a different situation, but at first I put my 944s on a some little rugs and then compared them with spikes. No comparison here in the big picture sense...more articulate top to bottom, yet still musical.

When I put in the HR-1s with spikes, they sounded really good, but I got curious about further vibration isolation, so got some Herbie's little fat gliders. Again, in an serious listening sense, a big difference...the spikes by comparison are harder with more sense of edge, particularly notable in the midrange. Whereas the gliders allow more balanced detail, as far as I can tell, more detail, but softer feeling and with more delicacy and texture....more nuance.

Not that this is necessarily the tool for you, but if you have not dealt with Steve at Herbie's, he knows his stuff, has a number of potential solutions for your situation, has lots of experience advising for taste and environment, and answers email quick...Also he has a good return policy.

EDIT: And by the way, herbiesaudiolabs isocups are really good under the Torii MKIII and MKIV, so I would guess would be good under the Mystery amp too. I use four, and move them around under the amp base to tune to my preference. Weird that this works so well, but it does.

NOTE􀁸 Balanced audio connectors are used mostly in professional audio electronics, such as highquality microphones and inter-equipment connections. The BDP-105 utilizes the 3-pin XLRconnector (shown below), which transmits a pair of differential signals (positive /negative). Theamplifier extracts the voltage difference between differential signals, thus the common noise canbe rejected and the signal integrity is improved.􀁸 In some audio systems the position s of "hot" (positive) and "cold" (negative) pins are switched.In this case please set ď XLR

I can see where one might want to experiment with coupling and decoupling speakers but I would think that decoupling all other equipment would always be desirable. †Yes? †No? †Before I isolated my ZMA I actually had bad feedback at high volume. †It was caused by the vibration transmitted through my stand.

In terms of coupling or de-coupling, I think variables make it pretty complex, each foot material, design, and size acting and sounding different. And finally it is the sound that wins. I agree though that decoupling, in my case, with Herbie's isocups, can be quite good for gear, especially with some balls of different materials to fine-tune tone with. But I have used hardwood cones under my DAC for a long time, almost always preferring this DAC sound over any other feet I have. And I tend prefer the sound of Synergistic Research MIGs (small metal bowls) under my Oppo. I also like weight on top of components, solidifying the sound further.

In the case of metal speaker spikes, though it is not decoupled, it is considerably less connected to the floor than with the plinth right on the floor. So the plinth is freed up for the most part, apparently a part of the sound of a speaker beyond deflecting passive bass outward. And the speaker can drain vibration to the point of the spike and floor, while floor vibration effects on the speaker seem minimized by the spike point being the connector. This is how it appears to me anyway, and I think the sound reflects this minimal coupling.

Herbie's gliders do decouple the speaker though, and it is a better sound to me, in this room, and with this floor. They have done considerable work on materials and design trying to get a neutral sound though.

I find feet fascinating. I think I use six different kinds in my system at this point, all having different characteristics vibration-wise and sound-wise.....nicely useful for a given component or speaker. But I really enjoy experimenting.

Yes, I've been using three different types of footers in my system, and I just changed one of the three. It's fun to experiment. I agree about decoupling speakers, in my instance it has bben the key. I'm using Ingress Engineering RollerBlocks--I wasn't as fond of them under components, but they're the cat's meow under my speakers. Four is better than three, which is not always the case--sometimes odd nunmbers work better.

Herbie's Iso-Cups work for all my components with the exception of two. I'm able to use them under my preamps again (had been using Tenderfeet for some time because my power cords interfered). I've found that the VooDoo Cable Iso-Pods are working very well under my turntable and Power Plant Premier, though I didn't liek them under my preamps. . . it's an interesting past time, playing around with isolation. Racks and stands are great too (though I've learned over time that my rack doesn't really isolate).

I've been experimenting with vibration isolation the past few years. I've used a variety of 2-shelf racks with different shelving materials with only limited success at best. Recently I purchased Maple Platforms with Isoblock footers from Mapleshade and have been very impressed with the sonic results.

My problem was always with vibration from the floor being transmitted through my equipment rack & shelves to the audio gear. The Main Maple Platform (18" wide, 15" deep, 4" thick, 25 pounds) is very stable compared to the floor when I'm cranking the system. The Second Maple Platform (15" wide, 12" deep, 2" thick, 10 pounds) is stable as well.

I really like the Mapleshade platforms as well. . . I have 2" and 4" ones beneath components on my Mapleshade Samson racks, and I have PS Audio PowerBases on top of those! Overkill, but as the Samson racks themselves don't really isolate, the platforms and PowerBases take my sound to a new level. I've stopped using the MapleShade Iso-Blocks and now use Herbie's Audio Lab "Grungebuster Dots" (the 2" size) under the platforms, but if I had platforms right on the floor I'd probably use the Iso-Blocks.

You guys and your whimpy little 4" thick maple stands. My Torii sits on a 5" thick slice of maple tree trunk! It has about 1/8" of shellac over the top and sits on a mahogany base.I cut the wood with a chainsaw, planed it level, sanded until it was shiny and then started shellacking until I went through 2 cans of Bulls Eye.My sub sits over in the corner on another hunk that is more like 6" thickSounds better? Probably not, but it sounds good enough for me.